A connecting device of that kind is known (U.S. Pat. No. 4,824,396). Connecting devices of that kind are used for example in the hubs of the steering wheels of motor vehicles. Increasingly, disposed in motor vehicle steering wheel hubs is a buffer gas bag which is inflated in fractions of a second in the event of substantial deceleration. That is effected by means of a firing capsule which is operative as a gas generator. The buffer gas bag and the firing capsule turn with the steering wheel. The steering column, through which the current for the firing capsule is supplied, is stationary. Now, the known connecting device just referred to above connects the rotating current connection of the firing capsule to the stationary current connection in the steering column. The spiral which is wound from the flat conductor cable is wound in a loose configuration with large clearance and spaces between the individual turns of the spiral. When the steering wheel is turned in one direction the spiral is further wound up and the windings are tightened towards each other. When the steering wheel is turned in the other direction, the spiral is unwound and the turns move away from each other to a certain extent. In that way the two current connections are always connected together in the same manner by way of the conductors of the flat conductor cable, even upon a rotary movement of the steering wheel. In addition to the firing capsule, it is also possible to envisage connection further current consumers or switches disposed in the steering wheel to a stationary current connection.
In order to achieve a high degree of elasticity, in order to provide for a low weight and in order to reduce the level of costs, a connecting device of the specified kind uses a flat conductor cable of small conductor cross-sections That means however that the mechanical strength thereof is reduced During the service life of a motor vehicle, the steering wheel thereof will be turned backwards and forwards innumerable times. That means that the flat conductor cable and in particular the ends thereof which issue from the housing are subjected to mechanical loadings.